At least 10 people were killed and 10 injured early Monday when a blast ripped through an electric trolley bus in Russia's Volgograd city, the second such in two days, the authorities said.
Russian Investigation Committee spokesman Vladimir Markin said the explosion could also be a terror attack, resembling the Sunday blast at the city's railway station, Xinhua reported.
Sunday's blast toll rose to 17, and at least 45 were injured, the authorities confirmed.
"A total of 62 people were afflicted by the explosion, 14 of them died at the scene and three died later in a hospital," the health ministry's press service told reporters Monday.
The two blasts in 48-hours in Volgograd came just six weeks before the Winter Olympics in Sochi.
The emergency situations ministry has sent a plane with medical modules to attend to the victims of Monday's explosion.
